Hcal 25ns constrained Method 2 for pre3

1. Fix the pulse shape used for MC to be number 105
2. If method 2 fails (nan issue) or not used (e.g., tstrig < ts4Min), it falls back now to Method 0
3. Add an option to control number of fit iterations
4. Separate out the hbheNegativeFlagSetter from the puCorrMethod switch. It was switched off when Method 1 was disabled. This hbheNegaviteFlagSetter is controlled by setNegativeFlags_ anyway.
5. Add print out to what method is actually activated
There are several numbers that are repeated probably 100 times in this PR: "10", "256", "25" at least. I suggest you make them const and put them in a separate header file (you can use namespace hcalConst {} inside it).